1. Field of the Invention
The invention relates to a heat exchanger (HEX) vessel with means for recirculating cleaning particles.
2. Description of the Related Art
It is suggested in U.S. Pat. Nos. 5,706,884, 5,676,201, 6,073,682 and 6,109,342 to provide a heat exchanger vessel in which a bundle of heat exchanger tubes is provided with means for circulating cleaning particles through the tubes to remove fouling from the inner walls of the tubes.
It is suggested in U.S. Pat. Nos. 6,070,652 and 6,223,809 to recirculate balls through a bundle of heat exchanger tubes to remove any fouling from the inner walls of the tubes.
The known systems are solely designed for cleaning the inner walls of heat exchanger tubes in a heat exchanger vessel.
German patent DE 1083058 suggests a heat exchanger wherein exhaust gases are cooled in the heat exchanger. This heat exchanger includes tubes through which cooling water is circulated and the cleaning particles are added to the flux of exhaust gases such the they remove debris and fouling from the outer surfaces of the cooling tubes. In this vessel the cooling tubes are arranged in a zig-zag pattern within the heat exchanger vessel such that the tubes are, along at least a substantial part of their length, arranged in a substantially transversal orientation relative to the direction of the cleaning particle laden flux of exhaust gases. A disadvantage of the known method is that the cooling tubes are subject to high and uneven wear and are cleaned in an uneven manner. Furthermore, the wall of the heat exchange is exposed to the high pressure and temperature of the exhaust gas, so that the heat exchanger vessel is a thick walled and heavy piece of equipment.